Bower 2X Teleconverter for Bower, Rokinon, Vivitar, Samyang, 500mm 800mm & 650-1300mm T-Mount Lens The Bower 2x Professional Multiplier is a high-quality teleconverter that delivers enhanced telephoto versatility. It multiplies the focal length by 2x, providing an affordable and portable way to extend your cameras reach. The specialized lens elements virtually eliminate color aberrations. The anti-reflection coating enhances light transmission efficiency, improves color consistency, and reduces flare. Uses a convenient T-Mount adapter, and is used between your SLR camera and lens Works ONLY with compatible T-mount Lenses